Phase-dependent Evaluation of Motor Cortex Excitability With TMS in Stroke

Neurological disorders, including stroke, are associated with impaired movement leading to significant negative effects on quality of life. Transcranial magnetic stimulation (TMS) is increasingly being explored as a rehabilitation strategy to enhance plasticity in motor regions.

However, it is not yet fully understood how TMS acts on motor circuits and what optimal stimulation parameters are. TMS is a noninvasive neuromodulation method which enables in vivo perturbation of neural activity in humans through the application of electromagnetic fields to the brain. TMS has an established safety profile and has been explored extensively in clinical trials for a range of neurological and psychiatric disorders. Particularly, in potential positive effects of TMS have been identified for stroke rehabilitation. However, significant variability in treatment outcomes across patients has been found, making it necessary to improve current stimulation protocols and to investigate basic mechanism of action . The investigators plan to study the effects of TMS to the motor cortex in individuals who suffered stroke for movement rehabilitation. The investigators plan to measure motor evoked potentials (MEPs) at different phases of the motor mu-rhythm measured with EEG. Mu rhythms are related to healthy movement execution. By this, the investigators characterize phase-dependent cortical excitability differences in stroke.

Inclusion criteria

• Suffering from chronic stroke, resulting in self-reported motor deficits (stroke occurring more than 6 months before study enrollment)
• Confident level of English language

Exclusion criteria

• Metal or electric implant in the head, neck, or chest area
• Upper extremity botulinum toxin treatment in the last 6 months
• Pregnancy or breastfeeding
• Prior occurrence of unprovoked seizure